Skin is the largest organ of the human body, with several important functions, including forming a physical barrier to the environment, protection against micro-organisms, allowing and limiting the inward and outward passage of water and electrolytes, ultraviolent radiation and toxic agents. Within the skin there are three structural layers: the epidermis, the dermis and the subcutis. Keratinocytes are the main cell type found within the epidermis. Fibroblasts are the predominant cell type within the dermis. The dermis is composed of a supportive extracellular matrix and contains bundles of collagen which run parallel to the skin surface. The role of fibroblasts within the dermis is to produce collagen, elastin, and structural proteoglycans. The collagen fibers constitute 70% of the dermis, giving it strength and toughness, while elastin provides normal elasticity and flexibility. The proteoglycans provide viscosity and hydration. Transforming growth factor β (TGF-β) is associated with the regulation of extracellular matrix production in human skin connective tissue. This factor is also of importance in the process of wound healing. Skin also is innervated and vascularized, and also contains small numbers of immune cells (e.g. mast cells, tissue macrophages, etc.).
Aging of human skin is associated with discoloration, wrinkling, and the sagging effect. These developments related to aging are dramatically visible in human skin which becomes dry, wrinkled, lax, and irregularly pigmented over time. Typically, aged skin is characterized by a flattening of the dermal-epidermal junction, increased atrophy, and a loss of elasticity of the dermal connective tissue. The loss of firmness and elasticity is commonly associated with the decrease/loss and disorganization of the major extracellular components, including collagen I (associated with being the primary cause of wrinkle formation), elastin, and large and small proteoglycans and glycosaminoglycans. Aging skin also possesses decreased TGF-β which results in reduced production of collagen and compromised wound healing. A histological analysis of aging in human skin has revealed a decrease in tissue thickness, disorganization of collagen, and accumulation of non-functional elastin.
Handheld skin cleansing devices are used for cosmetic purposes to efficiently cleanse facial skin. In some cases the devices claim additional benefits, such as exfoliation, smoothing/resurfacing, or deep cleaning. Such devices have one or more discrete electrically powered bristle brushes or nonwoven fabric pads that oscillate, vibrate, or a combination thereof to provide mechanical action of the brush(es) or pad(s) against the skin. Typically, a cleanser is applied to the bristles or the pad. Cleansing effectiveness of these devices depends on the bristle or pad type, pressure applied, and the type of cleanser.
One example of many is the SonicDermabrasion Facial Brush ST255, sold by PRETIKA® Corp. of Laguna Hills, Calif. The brush includes a handle and a round bristle brush head that rotates. Another example is the Pore Sonic Cleanser sold by Pobling of Seoul, S. Korea, which includes an oblong brush that is vibrated. Further examples are found in U.S. Patent Application Publication 20160045081 for Device And Method For Cleansing And Treating Skin, Ser. No 14/825316 and Device And Method For Cleansing And Treating Skin, PCT Application No. PCT/US2016/046738. Many examples similar to these are easily found in department stores, drug stores, and online.
Such rotating and/or vibrating heads provide cleaning action that is superior to the use of hands to clean one's face. However, it may be desirable to add to such devices a further form of skin treatment. Use of TENS (Transcutaneous Electrical Nerve Stimulation) is known for wound healing. (See, “Electrical stimulation to accelerate wound healing”, Gaurav Thakral, Javier LaFontaine, Bijan Najafi, Talal K. Talal, Paul Kim, Lawrence A. Lavery, Diabetic Foot & Ankle. 2013; 4: 10.3402/dfa.v4i0.22081. Published online 2013 Sep. 16. doi: 10.3402/dfa.v4i0.22081). There also exist TENS products that have been approved by the U.S. Food & Drug Administration for aesthetic skin application purposes, such as Rejuvenique Model #RJV10 from Salton, Inc.; Facial Toning System from Face Master; Nutritone from Isomera; and Trinity from Carol Cole—NuFace.
Skin that has been effectively cleansed may have its aesthetic aspects, such as presence of facial fine lines, mottled pigmentation, uneven skin tone, tactile roughness, global firmness appearance, and jaw-line contour, as well as desired attributes such as smoothness or radiance, improved. Accordingly, it may be desirable to provide aesthetic TENS treatment in combination with cleansing. Such treatment using electrical stimulation may be desirable to use in combination with a mechanical cleaning treatment, either before or after. The device described below shows in one or more embodiments how a TENS treatment feature may be added to certain types of handheld cleansing devices.